Attempting to get the original target for click events

[iangilman]

Fixes #1997

Here's my attempt to fix #1997, but it doesn't seem to be working. Here's my test code (for use in test/demo/basic.html):

var viewer = OpenSeadragon({
    id: "contentDiv",
    prefixUrl: "../../build/openseadragon/images/",
    tileSources: "../data/testpattern.dzi",
});

viewer.addHandler("open", function(event) {
    var elt = elt = document.createElement("div");
    elt.className = "runtime-overlay";
    elt.style.background = "white";
    elt.style.outline = "3px solid red";
    elt.style.width = "100px";
    elt.textContent = "Open console and click on me";
    viewer.addOverlay({
        element: elt,
        location: new OpenSeadragon.Point(0.6, 0.6),
        height: 0.1,
        placement: OpenSeadragon.Placement.TOP_LEFT,
        rotationMode: OpenSeadragon.OverlayRotationMode.NO_ROTATION
    });

});

viewer.addHandler('canvas-click', function(event) {
    console.log(event);
});

When I run it and click on the overlay, the event that's logged has an originalTarget but it's div.openseadragon-canvas (whereas we want it to be div.runtime-overlay).

I've tried doing console.log on the event during pointerDown handling, and those events are all in terms of the canvas. I'm not sure where to get the overlay, and why it's not showing up in the event.

@msalsbery do you have any insights on this?

[iangilman]

@msalsbery I've added documentation for the new property. I also went ahead and fixed the spelling of isStoppable, since I was in there :)

[msalsbery]

Looks good to me!

[msalsbery]

Nice fix! ;-)

[iangilman]

Great, thank you for the review!